We will continue studies on: 1. the catabolite gene activator protein (CGA protein) of Escherichia coli, the first gene activator protein to be isolated. 2. The molecular mechanism of action of bromodeoxyuridine (BrdU), a drug that selectivity blocks the expression of differentiated functions in mammalian cells. 3. The molecular mechanism of X chromosome inactivation in mammals. 4. Eukaryotic chromosome isolation, separation, and characterization; necessary for item 3 but also of interest in its own right. 5. The biological function of DNA methylation in gene regulation, and for X inactivation.